The present invention is directed to an integrated optical arrangement for demultiplexing a plurality of different wavelength channels and to the method of manufacturing the arrangement.
The transmission capacity of optical fibers can be significantly increased with optical wavelength multiplexing methods. Since optical wavelength multiplexing involves an optical multi-channel technique, the individual optical wavelength channels can be accessed in a simple way. A pre-condition for this technology, which is becoming widespread, however, are its reliability and, above all else, cost-beneficial transmission and reception modules.
A prior art for a channel spacing of approximately 5 nm comprises integrated optical arrangements for multiplexing a plurality of different wavelength channels with an optical diffraction grating that spectrally resolves the different wavelength channels that are fashioned in SiO.sub.2. These are disclosed, for example, in a German Patent Application P 39 13 242.0 of C. Cremer and A. Reichelt entitled "Verfahren zur Herstellung eines an einem Schichtwellenleiter ausgebildeten Beugungsgitters". Also, see articles by C. H. Henry, R. F. Kazarinov, Y. Shani, R. C. Kistler, V. Pol, and K. J. Orlowsky entitled "Four-channel wavelength division multiplexers and bandpass filters based on elliptical Bragg reflectors" Journal of Lightwave Technology, Vol. 8, No. 5 May 1990, pp. 748-755; and S. Valette, "State of the art of integrated optics technology at LETI for achieving passive optical components", Journal of Modern Optics, Vol. 35, No. 6 (1988), pp. 993-1005. Such an arrangement in InGaAsP/InP which comprises a high order is known. For example, see an article by M. Gibbon, G. H. B. Thompson, S. J. Clements, D. J. Moule, C. B. Rogers, and C. G. Curaton entitled "Optical performance of integrated 1.5 .mu.m grating wavelength-demultiplexer on InP-based waveguide", Electronics Letters, Vol. 25, No. 21, Oct. 12, 1989, pp. 1441-1442.